"If you lower corporate taxes from 35 percent to 15 or 20 percent, that goes to the bottom line. Those are earnings and then we know the stock market responds well to economic stimulus," the CEO and chief investment officer at Fairfax Global Markets said. "This market is going to look undervalued when we look back."

On Tuesday, investment legend Jack Bogle told "Squawk on the Street" he wasn't feeling "super confident" about the rally since he sees a struggle to reach the White House's goal of 3 percent to 3.5 percent economic growth.

"Financial market reconciliation lies ahead," said David Kostin, Goldman's chief U.S. equity strategist. "We are approaching the point of maximum optimism and the S&P 500 will give back recent gains as investors embrace the reality that tax reform is likely to provide a smaller, later tail wind to corporate earnings than originally expected."